很早之前写过MHA的文章，但是常常在技术群看到有同学问MHA搭建的问题，不是权限问题就是配置问题，我在这里就再次一写下配置过程以及快速的搭建。如果想知道更多的细节与原理，请参考：MySQL高可用架构之MHA
环境：
1主1从，manager放在从库。
主库：192.168.0.10
从库：192.168.0.20
两台机器的mysql安装完成初始化以后进行复制搭建，首先登录主库（192.168.0.10），查看pos点：
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 154 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
然后在主库（192.168.0.10）
添加复制账号以及mha用的账号
mysql> grant replication slave on *.* to 'repl'@'192.168.0.10' identified by 'repl';
Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> grant replication slave on *.* to 'repl'@'192.168.0.20' identified by 'repl';
Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> grant all on *.* to 'root'@'192.168.0.20' identified by '';
Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> grant all on *.* to 'root'@'192.168.0.10' identified by '';
Query OK, 0 rows affected, 1 warning (0.01 sec) mysql>
从库（192.168.0.10 ）change到mysql-bin.000001，pos点154
CHANGE MASTER TO MASTER_HOST='192.168.0.10',MASTER_USER='repl',MASTER_PASSWORD='repl',MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=154;
mysql> start slave;
Query OK, 0 rows affected (0.15 sec) mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.10
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 1344
Relay_Log_File: relaylog.000002
Relay_Log_Pos: 1510
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
复制到这来就搭建完成了，然后配置192.168.0.10和192.168.0.20 ssh互信。（两台机器都执行）
ssh-keygen -t rsa
ssh-copy-id -i /root/.ssh/id_rsa.pub '-p 22 192.168.0.10'
ssh-copy-id -i /root/.ssh/id_rsa.pub '-p 22 192.168.0.20'
安装MHA软件，首先安装epel源。（2台机器）
rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
安装依赖包
yum install perl-DBD-MySQL perl-Config-Tiny perl-Log-Dispatch perl-Parallel-ForkManager perl-Time-HiRes -y
安装MHA软件（两台机器）
tar xf mha4mysql-node-0.56.tar.gz
cd mha4mysql-node-0.56
perl Makefile.PL
make && make install tar xf mha4mysql-manager-0.56.tar.gz
cd mha4mysql-manager-0.56
perl Makefile.PL
make && make install
在从库（192.168.0.20）创建目录：
mkdir /data/mha//log
cd /data/mha//touch mha.cnf
mha.cnf配置文件内容如下：
[server default]
client_bindir=/usr/local/mysql/bin/
manager_log=/data/mha//log/manager.log
manager_workdir=/data/mha//log
master_binlog_dir=/data/mysql//binlog/
master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script= /usr/local/bin/master_ip_online_change
report_script=/usr/local/bin/send_report
init_conf_load_script=/usr/local/bin/load_cnf
remote_workdir=/data/mysql//mysqltmp
#secondary_check_script= /usr/local/bin/masterha_secondary_check -s 192.168.0.30 -s 192.168.0.40
user=root
ping_interval=
repl_user=repl
ssh_port=
ssh_user=root
max_ping_errors= [server1]
hostname=192.168.0.10
port= [server2]
candidate_master=
check_repl_delay=
hostname=192.168.0.20
port=
编辑文件 /usr/local/bin/load_cnf 里面的密码修改成对应的密码
#!/usr/bin/perl print "password=123\n";
print "repl_password=repl\n";
执行chek命令查看复制是否正常：
[root@dbserver-yayun- ]# masterha_check_repl --conf=/data/mha//mha.cnf
Mon Mar :: - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Mar :: - [info] Reading application default configuration from /data/mha//mha.cnf..
Mon Mar :: - [info] Updating application default configuration from /usr/local/bin/load_cnf..
Mon Mar :: - [info] Reading server configuration from /data/mha//mha.cnf..
Mon Mar :: - [info] Setting max_ping_errors to , ping_interval to .
Mon Mar :: - [info] MHA::MasterMonitor version 0.56.
Mon Mar :: - [info] GTID failover mode =
Mon Mar :: - [info] Dead Servers:
Mon Mar :: - [info] Alive Servers:
Mon Mar :: - [info] 192.168.0.10(192.168.0.10:)
Mon Mar :: - [info] 192.168.0.20(192.168.0.20:)
Mon Mar :: - [info] Alive Slaves:
Mon Mar :: - [info] 192.168.0.20(192.168.0.20:) Version=5.7.-log (oldest major version between slaves) log-bin:enabled
Mon Mar :: - [info] Replicating from 192.168.0.10(192.168.0.10:)
Mon Mar :: - [info] Primary candidate for the new Master (candidate_master is set)
Mon Mar :: - [info] Current Alive Master: 192.168.0.10(192.168.0.10:)
Mon Mar :: - [info] Checking slave configurations..
Mon Mar :: - [info] read_only= is not set on slave 192.168.0.20(192.168.0.20:).
Mon Mar :: - [warning] relay_log_purge= is not set on slave 192.168.0.20(192.168.0.20:).
Mon Mar :: - [info] Checking replication filtering settings..
Mon Mar :: - [info] binlog_do_db= , binlog_ignore_db=
Mon Mar :: - [info] Replication filtering check ok.
Mon Mar :: - [info] GTID (with auto-pos) is not supported
Mon Mar :: - [info] Starting SSH connection tests..
Mon Mar :: - [info] All SSH connection tests passed successfully.
Mon Mar :: - [info] Checking MHA Node version..
Mon Mar :: - [info] Version check ok.
Mon Mar :: - [info] Checking SSH publickey authentication settings on the current master..
Mon Mar :: - [info] HealthCheck: SSH to 192.168.0.10 is reachable.
Mon Mar :: - [info] Master MHA Node version is 0.56.
Mon Mar :: - [info] Checking recovery script configurations on 192.168.0.10(192.168.0.10:)..
Mon Mar :: - [info] Executing command: save_binary_logs --command=test --start_pos= --binlog_dir=/data/mysql//binlog/ --output_file=/data/mysql//mysqltmp/save_binary_logs_test --manager_version=0.56 --start_file=mysql-bin.
Mon Mar :: - [info] Connecting to root@192.168.0.10(192.168.0.10:)..
Creating /data/mysql//mysqltmp if not exists.. ok.
Checking output directory is accessible or not..
ok.
Binlog found at /data/mysql//binlog/, up to mysql-bin.
Mon Mar :: - [info] Binlog setting check done.
Mon Mar :: - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Mon Mar :: - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='root' --slave_host=192.168.0.20 --slave_ip=192.168.0.20 --slave_port= --workdir=/data/mysql//mysqltmp --target_version=5.7.-log --manager_version=0.56 --client_bindir=/usr/local/mysql/bin/ --relay_dir=/data/mysql//relaylog --current_relay_log=relaylog. --slave_pass=xxx
Mon Mar :: - [info] Connecting to root@192.168.0.20(192.168.0.20:)..
Checking slave recovery environment settings..
Relay log found at /data/mysql//relaylog, up to relaylog.
Temporary relay log file is /data/mysql//relaylog/relaylog.
Testing mysql connection and privileges..mysql: [Warning] Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Mon Mar :: - [info] Slaves settings check done.
Mon Mar :: - [info]
192.168.0.10(192.168.0.10:) (current master)
+--192.168.0.20(192.168.0.20:) Mon Mar :: - [info] Checking replication health on 192.168.0.20..
Mon Mar :: - [info] ok.
Mon Mar :: - [info] Checking master_ip_failover_script status:
Mon Mar :: - [info] /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=192.168.0.10 --orig_master_ip=192.168.0.10 --orig_master_port= IN SCRIPT TEST====/sbin/ifconfig eth1: down==/sbin/ifconfig eth1: 192.168.0.88/=== Checking the Status of the script.. OK
Mon Mar :: - [info] OK.
Mon Mar :: - [warning] shutdown_script is not defined.
Mon Mar :: - [info] Got exit code (Not master dead). MySQL Replication Health is OK.
主库（192.168.0.10）执行命令，启动vip：
/sbin/ifconfig eth1: 192.168.0.88/
在线切换，把主库切到192.168.0.20
masterha_master_switch --master_state=alive --conf=/data/mha//mha.cnf --new_master_host=192.168.0.20 --new_master_port= --orig_master_is_new_slave
输出如下：
Mon Mar :: - [info] MHA::MasterRotate version 0.56.
Mon Mar :: - [info] Starting online master switch..
Mon Mar :: - [info]
Mon Mar :: - [info] * Phase : Configuration Check Phase..
Mon Mar :: - [info]
Mon Mar :: - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Mar :: - [info] Reading application default configuration from /data/mha//mha.cnf..
Mon Mar :: - [info] Updating application default configuration from /usr/local/bin/load_cnf..
Mon Mar :: - [info] Reading server configuration from /data/mha//mha.cnf..
Mon Mar :: - [info] Setting max_ping_errors to , ping_interval to .
Mon Mar :: - [info] GTID failover mode =
Mon Mar :: - [info] Current Alive Master: 192.168.0.10(192.168.0.10:)
Mon Mar :: - [info] Alive Slaves:
Mon Mar :: - [info] 192.168.0.20(192.168.0.20:) Version=5.7.-log (oldest major version between slaves) log-bin:enabled
Mon Mar :: - [info] Replicating from 192.168.0.10(192.168.0.10:)
Mon Mar :: - [info] Primary candidate for the new Master (candidate_master is set) It is better to execute FLUSH NO_WRITE_TO_BINLOG TABLES on the master before switching. Is it ok to execute on 192.168.0.10(192.168.0.10:)? (YES/no): yes
Mon Mar :: - [info] Executing FLUSH NO_WRITE_TO_BINLOG TABLES. This may take long time..
Mon Mar :: - [info] ok.
Mon Mar :: - [info] Checking MHA is not monitoring or doing failover..
Mon Mar :: - [info] Checking replication health on 192.168.0.20..
Mon Mar :: - [info] ok.
Mon Mar :: - [info] 192.168.0.20 can be new master.
Mon Mar :: - [info]
From:
192.168.0.10(192.168.0.10:) (current master)
+--192.168.0.20(192.168.0.20:) To:
192.168.0.20(192.168.0.20:) (new master)
+--192.168.0.10(192.168.0.10:) Starting master switch from 192.168.0.10(192.168.0.10:) to 192.168.0.20(192.168.0.20:)? (yes/NO): yes
Mon Mar :: - [info] Checking whether 192.168.0.20(192.168.0.20:) is ok for the new master..
Mon Mar :: - [info] ok.
Mon Mar :: - [info] 192.168.0.10(192.168.0.10:): SHOW SLAVE STATUS returned empty result. To check replication filtering rules, temporarily executing CHANGE MASTER to a dummy host.
Mon Mar :: - [info] 192.168.0.10(192.168.0.10:): Resetting slave pointing to the dummy host.
Mon Mar :: - [info] ** Phase : Configuration Check Phase completed.
Mon Mar :: - [info]
Mon Mar :: - [info] * Phase : Rejecting updates Phase..
Mon Mar :: - [info]
Mon Mar :: - [info] Executing master ip online change script to disable write on the current master:
Mon Mar :: - [info] /usr/local/bin/master_ip_online_change --command=stop --orig_master_host=192.168.0.10 --orig_master_ip=192.168.0.10 --orig_master_port= --orig_master_user='root' --orig_master_password='' --new_master_host=192.168.0.20 --new_master_ip=192.168.0.20 --new_master_port= --new_master_user='root' --new_master_password='' --orig_master_ssh_user=root --new_master_ssh_user=root --orig_master_is_new_slave
Mon Mar :: Set read_only on the new master.. ok.
Mon Mar :: Drpping app user on the orig master..
Mon Mar :: Set read_only= on the orig master.. ok.
Mon Mar :: Killing all application threads..
Mon Mar :: done.
Mon Mar :: - [info] ok.
Mon Mar :: - [info] Locking all tables on the orig master to reject updates from everybody (including root):
Mon Mar :: - [info] Executing FLUSH TABLES WITH READ LOCK..
Mon Mar :: - [info] ok.
Mon Mar :: - [info] Orig master binlog:pos is mysql-bin.:.
Mon Mar :: - [info] Waiting to execute all relay logs on 192.168.0.20(192.168.0.20:)..
Mon Mar :: - [info] master_pos_wait(mysql-bin.:) completed on 192.168.0.20(192.168.0.20:). Executed events.
Mon Mar :: - [info] done.
Mon Mar :: - [info] Getting new master's binlog name and position..
Mon Mar :: - [info] mysql-bin.:
Mon Mar :: - [info] All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.0.20', MASTER_PORT=, MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=, MASTER_USER='repl', MASTER_PASSWORD='xxx';
Mon Mar :: - [info] Executing master ip online change script to allow write on the new master:
Mon Mar :: - [info] /usr/local/bin/master_ip_online_change --command=start --orig_master_host=192.168.0.10 --orig_master_ip=192.168.0.10 --orig_master_port= --orig_master_user='root' --orig_master_password='' --new_master_host=192.168.0.20 --new_master_ip=192.168.0.20 --new_master_port= --new_master_user='root' --new_master_password='' --orig_master_ssh_user=root --new_master_ssh_user=root --orig_master_is_new_slave
Mon Mar :: Set read_only= on the new master.
Mon Mar :: Creating app user on the new master..
Mon Mar :: - [info] ok.
Mon Mar :: - [info]
Mon Mar :: - [info] * Switching slaves in parallel..
Mon Mar :: - [info]
Mon Mar :: - [info] Unlocking all tables on the orig master:
Mon Mar :: - [info] Executing UNLOCK TABLES..
Mon Mar :: - [info] ok.
Mon Mar :: - [info] Starting orig master as a new slave..
Mon Mar :: - [info] Resetting slave 192.168.0.10(192.168.0.10:) and starting replication from the new master 192.168.0.20(192.168.0.20:)..
Mon Mar :: - [info] Executed CHANGE MASTER.
Mon Mar :: - [info] Slave started.
Mon Mar :: - [info] All new slave servers switched successfully.
Mon Mar :: - [info]
Mon Mar :: - [info] * Phase : New master cleanup phase..
Mon Mar :: - [info]
Mon Mar :: - [info] 192.168.0.20: Resetting slave info succeeded.
Mon Mar :: - [info] Switching master to 192.168.0.20(192.168.0.20:) completed successfully.
关于配置文件中的参数：
max_ping_errors=40，这个是修改了源码，增加了检测次数的定义，默认是3次，太容易误切换。
启动管理进程：
/usr/bin/nohup /usr/local/bin/masterha_manager --conf=/data/mha//mha.cnf --ignore_last_failover > /data/mha//log/manager.log >& &
在主库（192.168.0.10）封掉ip，可以看到日志输出。
iptables -I INPUT -s 192.168.0.20 -j DROP
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
Mon Mar :: - [warning] Connection failed time(s)..
Mon Mar :: - [warning] Got error on MySQL connect: (Can't connect to MySQL server on '192.168.0.10' (4))
修改以后的软件包下载地址：链接：http://pan.baidu.com/s/1c3qg70 密码：f9u2